【国外标准】 Standard Practice for Determination of Minimum Immersion Depth and Assessment of Temperature Sensor Measurement Drift

5.1 This practice provides a means for the users of ASTM Committee D02 standards to monitor the drift in sensed temperature of liquid-in-glass thermometer (LiG), and digital contact thermometers (DCT). Digital contact thermometers are sometimes referred to as portable electronic thermometers (PET) or simply digital thermometers.5.2 This practice is not suitable for determining the accuracy or calibration of a temperature-measuring device as the error in the ice bath temperature can be greater than 0.02 °C. For greater accuracy, the user should use Practice E563 to prepare the ice bath.5.3 The ice point is a common practical industrial reference point of thermometry. The ice point is relatively simple to realize and provides a readily available natural fixed-point reference temperature.5.4 This practice only checks the measurement drift at a single temperature. It will not detect a change in measurement response with change in temperature. Temperature-measuring devices should be recalibrated at set intervals. See device supplier for recommendations.5.5 This practice provides a technique to determine minimum immersion depth of the sensing probe of the thermometer using an ice bath. The minimum immersion depth determined by this practice may change when the differential temperature differs significantly from the conditions described. A greater differential will likely increase the minimum immersion depth.1.1 This practice describes two procedures for use with temperature measurement devices. Methodology is described for determining minimum immersion depth for thermal sensors, in particular RTDs or similar temperature sensors. Included is a procedure for consistently preparing a reference bath for the purpose of monitoring measurement drift of thermal sensors such as liquid-in-glass or digital contact thermometers.1.2 This practice focuses on temperature measurement drift in a laboratory. If the user requires greater measurement accuracy, then they should follow the instructions in Practice E563.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.